This is a serious question -- you really can do a venue, stickers, beers, and other stuff for $4 pp? Because I am struggling to see how that works. My rough guess from having thrown events would be $14 pp for decent food, beers and some nicer-than-soda non-alcoholic alternatives, etc.
The venue should be available for free if your meetup is attractive to people that could be potential employees of the hosts. And why do you feel the need to give people free food and drinks? Reframe the issue : Everyone who attends should be motivated to come to the event for the content, rather than free food on their way home.
Edit: After reading a bit more about it, the cost is to the users, not organizers, which makes even less sense. Why would anyone ever RSVP instead of just showing up?